四环素类药物在水产品中的存在形态研究及其分析应用

Study on the Form of Tetracycline Antibiotics in Aquatic Products and Its Analytical Application

采用紫外分光光度法研究了四环素类药物(Tetracyclines,TCs)在不同pH条件下分子结构的变化,用分子荧光法、高效液相色谱法(HPLC)探讨了TCs在蛋白质基体中的存在形态,同时讨论了蛋白质对提取水产品样品中TCs残留的影响。结果表明,TCs与蛋白质有较强结合作用;适当浓度的(NH4)2SO4与HPLC流动相(甲醇-乙腈-0.02 mol/L草酸混合溶液,20∶20∶60,V/V)混合提取液可引起蛋白质缓慢且完全变性,导致蛋白质与TCs络合物离解,释放结合的药物,从而提高蛋白质样品中TCs残留提取的效率。本方法用于测定水产品中的土霉素、四环素、金霉素和强力霉素,测定回收率为88.2%～95.4%,RSD为1.3%～4.9%,检出限为14.8～39.2 ng/g。本方法操作步骤简单、快速、可靠。

Molecular fluorescence spectrometry and High performance liquid chromatography （HPLC） were applied to study the form of tetracyclines （TCs） in protein matrix of aquatic products. The molecular form of TCs in different media of pH value was studied by UV-VIS. The influence of proteins on extraction of TCs from aquatic products samples was also discussed. The results showed that there was a strong binding effect between TCs and protein. In the mixture of ammonium sulfate aqueous solution and mobile phase of HPLC （ methanol ： acetonitrile： 0.02 mol/L oxalic acid aqueous solution = 20：20：60, V/V）, a slow but full protein denaturation took place, which caused the dissociation of TCs-protein complex. Therefore, TCs residues in aquatic products were extracted with high extraction efficiencies. This method has been applied to the determination of 4 kinds of TCs （oxytetracycline, tetracycline, chlortetracycline and doxycycline） residues in the fish and shrimp sampies. The detection limits were in the range of 14.8-39.2 ng/g, and the spiked recoveries were 88.2% - 95.4% with RSD 1.3%-4.9%. The method was simple, quick and reliable.